Preheat the oven to 350°F. Line an 8x4" loaf pan with parchment paper.
In a large mixing bowl, combine the melted butter, coconut sugar, and vanilla extract. Stir until combined. Add the mashed bananas, lemon juice, and eggs. Stir until combined.
Add the baking powder, baking soda, tapioca flour, coconut flour, and cinnamon. Stir until the batter is smooth. Fold in the 1/2 cup of chocolate chips.
Pour the batter into the loaf pan and spread it out evenly. Sprinkle the remaining chocolate chips on top of the batter.
Bake for 55-60 minutes. The edges should be lightly browned and a toothpick inserted into the center should come out clean.
Let the bread cool for 10 minutes before removing it from the loaf pan and placing it on a cooling rack to finish cooling. You can slice the bread once it is completely cooled.